Balanced slide-valve.



PATENTED MAR. 31,1903; J. T. WILSON.

. BALANCED s APPLICATION PI LIDE VALVE.

LED JULY 6, 1900.

a SHEETS-SHEET 1.

no MODEL.

.. as in Q w wk No.724,363.' PATENTED MAR.31,1903.

J. T. WIL} ANGED SLIDE LVE.

IOATION FILED J'U 3 SHEETS-SHEET 2.

N0 MODEL.

PATENTED MAR; 31', 1903. J. '1. WILSON.

BALANCED sL '1) VALVE.

APPLICATION PIL ULY 6. 1900.

a sHnzTs-sim'r a.

30 MODEL w&

MW. QM

644 Awd/dy UNITED STATES PATENT OFFICE.-

JOHNTFWILSON, OF JERSEY SHORE, PENNSYLVANIA;

BALANCED SLIDE-VALVE.

Application filed July 6, 1900.

To (t lt whom it may concern);

Be it known that I, JOHN T. WiLSON, a citizen of the United States, residing at Jersey Shore, in the county of Lycoming and State of Pennsylvania, have invented certain new and useful Improvements in Balanced Slide- Valves, of which the following is a specification.

My invention relates to balanced slidevalves, and in particular to that type in which a certain area at the back of the valve is normally isolated or shut ofi from the action of steam or other motive-fluid pressure, my object being the provision of means whereby this area may be varied in extent to correspond with certain positions which the valve may occupy relative to the valve-seat.

My invention consists, imprimis, in a valve having two or more inclosed areas at the back thereof from which motive fluid isentirely excluded during a certain portion or portions of the valve travel and to one or more ofwhich inclosed areas motive fluid can be admitted during a certain portion or portions of the valve travel.

It further consists in certain novelties of construction and combinations of parts hereinafter set forth, and specified in the claims.

The accompanying drawings illustrate an example of the physical embodiment of my invention constructed according to the best of the several modes I have so far devised for the practical application of the principle.

Figure 1 is a sectional elevation view of a well-known type of slide-valve with my improvements added, showing the valve in its central position relative to the seat; Fig. 2, a plan view of a part of the under surface of the bearing-plate or steam-chest cover. Fig. 3 is a view similar to Fig. 1, with the valve occupying a position in which steam is admitted to a previously-inclosed space or area at the back thereof. Fig. 4 is a similar view in which steam is being exhausted from the aforesaid space or area to the exhaust-cavity of the valve.

Referring to the several figures, the numeral 1 designates the bearing-plate or steamchest cover; 2, the valve-seat; 3, the body of the valve; 4, the circular top ofthe body, which maybe a plate made separate and secured in position in any way; 5, the circular SPECIFICATION forming part of Letters Patent No. 724,363, dated March 31, 190:3.

Serial No. 22,746. (No model.)

edges of the top of the body and the round plate; 11, a lap-joint of any kind which will allow expansion and contraction of the ring; 12, a downwardly-projecting flange on the under surface of the round plate fitting inside the circular flange 6, but some distance therefrom, so as to leave an open space sufficient to allow the round plate to rock relative to the top of the body of the valve, or vice versa; 13, a circular plain area upon the under surface of the round plate and outside the flange 12 of the same; 14:, a beveled snap ring provided with a suitable lap-joint which fits the beveled side 7 of the flange 6 and the circular plain area 13 upon the under side of the round plate; 15, the exhaust-cavity; 16, a circular space or area at the back of the valve, from which steam is normally excluded.

-17 represents passages from the space 16 to the exhaust-cavity;-18, a space or area between the dou'ble-beveled ring 10 and the snap ring 14, from which at certain portions of the valve travel steam is excluded.

19 represents slots in the under surface of the bearing-plate or steam-chest cover; 20, series of pockets in the under surface of the bearing-plate or steam-chest cover; 21, passages in the round plate leading from the space or area 18 to the top surface of the round plate; 22, openings at the ends of the passages; 23, openings midway of the lengths 'of the passages 21 or otherwise located; 24, passages through the round plate communicating with the inclosed space or area 16 at the back of the valve; 25, edges of the valveseat; 26, points which indicate the extreme travel of the valve, and 27 represents points midway between the extreme points of the valve travel and the edges of the valve-seat. The modus operandi of the valve is as follows: Assuming that the valve is balanced, as is usual in all positions'of its travel when the face of the valve does not overlap the valvess'eat, any projection beyond the edge 25 of the seat will expose a given area of the Valveface to an upward steam-pressure at 28. To

too

balance this pressure, steam is admitted to the space or area 18 by way of the opening 23 and passage 21, as shown by the arrows in Fig. 3, where the valve has traveled to the point 27. Steam-pressure is retained in the space 18 during the further outward travel of the valve to the point 26 and its backward travel to the point 29, where the opening 22 at the end of the passage 21 and the passage 24 are in communication with a pocket 20. In this latter position of the valve steam in the space 18 will be exhausted into the space 16 at the back of the valve and thence to the exhaust-cavity, as indicated by the arrows in Fig. 4. As the valve travels farther toward the left steam is successively exhausted through the remaining pockets of the series and also through the series of pockets in the opposite side of the face of the bearing-plate or steam-chest cover. When the valve travels toward the left, the same operation is repeated.

From the foregoing it will be seen that I have produced a slide-valve which is balanced at all positions of its travel relative to the valve-seat.

While I have illustrated only one example of the physical embodiment of my invention, I do not thereby intend to limit the scope of the same to such example, inasmuch as it may be embodied under other forms and by difierent modes of applying the principle.

Modifications and changes in construction and in the location of parts may also be made at will without constituting a substantial departure. For instance, in lieu of the slots 19 in the bearing-platel may useaslot oraseries of holes extending entirely through the plate, the number of pockets 20 may be increased or diminished and differently located, the space or area 18 may be enlarged or contracted,

the number of spaces or areas to which motive fluid may be admitted at certain positions of the valve travel may be increased, the space 18 at the rightmay be isolated from the space 18 at the left, the slots and pockets made in the under surface of the steam-chest cover, and many other changes he introduced.

Live steam may be admitted to the space or area,18 at any time when desired; but in the example illustrated it should be admitted only when the valve overtravels the seat-.

steam will be admitted to the previously-inclosed space or spaces and the balance be restored. The value of my improvements will be appreciated by those familiar with the damage, annoyance, and numerous deleterious effects caused by slide-valves which are not properly balanced.

What I claim is 1. Aslide-valve havinga plurality of spaces or areasformed by the top of the valve, the round plate or'ring and the rings 10 and 14 from which motive-fluid pressure is excluded when the valve occupies the central position of its travel, and to one of which spaces or areas steam is admitted as the valve travels to the right or left and overlaps the valveseat; said motive fluid being exhausted as the valve returns toward its central position.

2. The combination with the top of a valve and bearing-plate or steam-chest cover, of rings forming an inclosed space entirely around the outer edge of the valve, means for introducing steam to said space when the valve overtravels its seat, and means embracing pockets in the bearing-plate for exhausting the steam when the valve returns to its seat.

3. The combination with a valve having a plurality of suitably-divided spaces or areas between the top of the valve body and a round plate or ring, of means in connection with the bearing-plate or steam-chest cover for introducing motive fluid to one or more of said spaces or areas when the valve overlaps its seat, and means for discharging said motive fluid from said space or spaces; in substance as set forth.

4. The combination with a valve having a plurality of suitably-divided spaces or areas, of means in connection with the bearing-plate or steam-chest cover and round plate for introducing motive fluid to and discharging it from one or more of said spaces or areas re spectively when the valve travels beyond the valve-seat and overlaps and when it returns to the same.

5. The combinationwith a valve having a plurality of suitably-divided spaces or areas, of means in connection with the bearing-plate or steam-chest cover and round plate, consisting of slots, pockets, and passages, for introducing motive fluid to and discharging motive fluid from one or more of said spacesorareas.

6. The combination with a valve having a plurality of suitably-divided spaces or areas,

as 16 and 18, of means for introducing motive fluid to space, 18, when the valve overtravels its seat, and means for discharging said motive fluid to the space, 16, as the valve returns toward a central position upon its seat.

In testimony whereof I afliix my signature in presence of two witnesses.

JOHN T. WILSON. 

